U.S. patent application number 14/906112 was filed with the patent office on 2016-11-10 for light guide plate and display device.
This patent application is currently assigned to BOE TECHNOLOGY GROUP CO., LTD.. The applicant listed for this patent is BOE OPTICAL SCENCE AND TECHNOLOGY CO., LTD., BOE TECHNOLOGY GROUP CO., LTD.. Invention is credited to Nuowei GONG, Shanfei Xu, Boran ZHENG.
Application Number | 20160327726 14/906112 |
Document ID | / |
Family ID | 52851640 |
Filed Date | 2016-11-10 |
United States Patent
Application |
20160327726 |
Kind Code |
A1 |
GONG; Nuowei ; et
al. |
November 10, 2016 |
LIGHT GUIDE PLATE AND DISPLAY DEVICE
Abstract
A light guide plate (LGP) and a display device are disclosed.
The LGP comprises at least one mesh point; each mesh point is
provided with a plurality of microstructures; and all the
microstructures on each mesh point are arranged on the same curved
surface. The LGP can solve the problem that incident light is
subjected to total reflection in the LGP so that the luminous
uniformity of the LGP can be improved.
Inventors: |
GONG; Nuowei; (Beijing,
CN) ; ZHENG; Boran; (Beijing, CN) ; Xu;
Shanfei; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOE TECHNOLOGY GROUP CO., LTD.
BOE OPTICAL SCENCE AND TECHNOLOGY CO., LTD. |
Beijing
Suzhou, Jiangsu |
|
CN
CN |
|
|
Assignee: |
BOE TECHNOLOGY GROUP CO.,
LTD.
Beijing
CN
BOE OPTICAL SCENCE AND TECHNOLOGY CO., LTD.
Suzhou, Jiangsu
CN
|
Family ID: |
52851640 |
Appl. No.: |
14/906112 |
Filed: |
August 21, 2015 |
PCT Filed: |
August 21, 2015 |
PCT NO: |
PCT/CN2015/087814 |
371 Date: |
January 19, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/0043 20130101;
G02B 6/00 20130101; G02B 6/0036 20130101; G02B 6/0061 20130101 |
International
Class: |
F21V 8/00 20060101
F21V008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 6, 2015 |
CN |
201510005708.0 |
Claims
1. A light guide plate (LGP), comprising at least one mesh point
provided with microstructures, wherein all the microstructures on
each mesh point are arranged on a same curved surface.
2. The LGP according to claim 1, wherein the curved surface is a
spherical curved surface.
3. The LGP according to claim 1, wherein a top surface of the
microstructure is a cambered surface.
4. The LGP according to claim 1, wherein the microstructures,
arranged on a same circumference, on the curved surface have a same
shape and size; and a plane provided with the circumference is
parallel to a light-emitting surface of the LGP,
5. The LGP according to claim 1, wherein the curved surface is
bisected by N parabolas; a starting point of the parabola is a
vertex of the curved surface, and an end point is disposed on a
bottom surface of the mesh point; N.gtoreq.1; and the
microstructures are sequentially arranged from the starting point
to the end point of the parabola and have a same shape, and sizes
thereof are gradually increased.
6. The LGP according to claim 1, wherein a shape of the bottom
surfaces of the microstructures includes quadrangle, pentagon or
hexagon.
7. The LGP according to claim 5, wherein positions of the
microstructures on the parabola satisfy the formula: [ 1 + P y ( i
) ( 1 - .DELTA..PHI. 2 ) ] .DELTA. z ( i + 1 ) 2 - 2 P .DELTA. z (
i + 1 ) - y ( i ) 2 .DELTA..PHI. 2 = 0 ##EQU00010## wherein P is
twice larger than a focal length of the parabola; y.sub.(i) is
coordinates of the microstructures in a y direction in a coordinate
system of the parabola; .DELTA.z.sub.(i+1) is a distance between
centerlines of two adjacent microstructures along a z direction in
the coordinate system of the parabola; and .DELTA..phi. is an
included angle between the centerlines of the two adjacent
microstructures on the parabola.
8. The LOP according to claim 7, wherein an inclination angle
.alpha..sub.(i) of the microstructure on the parabola satisfies the
following formula: .alpha. ( i ) = tan - 1 P y ( i ) .
##EQU00011##
9. The LGP according to claim 8, wherein a magnification ratio
.beta..sub.(i) of the two adjacent microstructures satisfies the
following formula: .beta. ( i ) = .DELTA. l z ( i + 1 ) .DELTA. l
.PHI. ( i ) ##EQU00012## wherein .DELTA.l.sub.z(i+1) is a length of
the parabola between the centerlines of the two adjacent
microstructures along the z direction in the coordinate system of
the parabola; and .DELTA.l.sub..phi.(i) is a diameter of the bottom
surface of each microstructure.
10. The LGP according to claim 1, wherein the curved surface is
recessed in the LGP or projected out of the LGP.
11. The LGP according to claim 2, wherein the spherical curved
surfaces of all the mesh points on the LGP have a same curvature
radius.
12. A display device comprising the LGP according to claim 1.
13. The LGP according to claim 2, wherein a top surface of the
microstructure is a cambered surface.
14. The LGP according to claim 4, wherein the curved surface is
bisected by N parabolas; a starting point of the parabola is a
vertex of the curved surface, and an end point is disposed on a
bottom surface of the mesh point; N.gtoreq.1; and the
microstructures are sequentially arranged from the starting point
to the end point of the parabola and have a same shape, and sizes
thereof are gradually increased.
15. The LOP according to claim 4, wherein a shape of the bottom
surfaces of the microstructures includes quadrangle, pentagon or
hexagon.
16. The LOP according to claim 5, wherein a shape of the bottom
surfaces of the microstructures includes quadrangle, pentagon or
hexagon.
17. The LOP according to claim 3, wherein the curved surface is
recessed in the LOP or projected out of the LOP.
18. The LOP according to claim 4, wherein the curved surface is
recessed in the LOP or projected out of the LOP.
19. The LOP according to claim 5, wherein the curved surface is
recessed in the LOP or projected out of the LOP.
20. The LOP according to claim 6, wherein the curved surface is
recessed in the LOP or projected out of the LOP.
Description
TECHNICAL FIELD
[0001] Embodiments of the present disclosure relate to a light
guide plate and a display device.
BACKGROUND
[0002] With the rapid development of display technologies, liquid
crystal displays (LCDs), as flat-panel display, become more and
more widely applied in high-performance display fields due to the
characteristics of small volume, low power consumption,
non-radiation, low manufacturing cost, etc.
[0003] An LCD is a passive luminescent device and requires a
backlight unit (BLU) to provide a light source for the LCD, so that
the LCD can display images. The BLU may include a light source and
a light guide plate (LGP); the light source is disposed facing an
incident surface of the LGP; and the LGP is configured to guide the
transmission direction of light beams emitted from the light source
and convert a line or point light source into a surface light
source. The LGP is a key component of the BLU, has the main
function of reasonably guiding the scattering direction of light,
and hence provides the surface light source with high brightness
and good uniformity for an LCD panel.
SUMMARY
[0004] Embodiments of the present disclosure provide a light guide
plate, which comprises at least one mesh point provided with
microstructures, wherein all the microstructures on each mesh point
are arranged on the same curved surface.
[0005] Optionally, the curved surface is a spherical curved
surface.
[0006] Optionally, a top surface of the microstructure is a
cambered surface.
[0007] Optionally, the microstructures, arranged on the same
circumference, on the curved surface have a same shape and size;
and a plane provided with the circumference is parallel to a
light-emitting surface of the LGP.
[0008] Optionally, the curved surface is bisected by N parabolas; a
starting point of the parabola is a vertex of the curved surface,
and an end point is disposed on a bottom surface of the mesh point;
N.gtoreq.1; and the microstructures are sequentially arranged from
the starting point to the end point of the parabola and have same
shape and sequentially ascending size.
[0009] Optionally, the shape of the bottom surfaces of the
microstructures includes quadrangle, pentagon or hexagon.
[0010] Optionally, the position of the microstructure on the
parabola satisfies the formula:
[ 1 + P y ( i ) ( 1 - .DELTA..PHI. 2 ) ] .DELTA. z ( i + 1 ) 2 - 2
P .DELTA. z ( i + 1 ) - y ( i ) 2 .DELTA..PHI. 2 = 0
##EQU00001##
wherein P is twice larger than a focal length of the parabola; y(i)
is the coordinate of the microstructure in the y direction in the
coordinate system of the parabola; .DELTA.z.sub.(i+1) is the
distance between centerlines of two adjacent microstructures along
the z direction in the coordinate system of the parabola; and
.DELTA..phi. is an included angle between the centerlines of the
two adjacent microstructures on the parabola.
[0011] Optionally, the inclination angle .alpha..sub.(i) of the
microstructure on the parabola satisfies the formula:
.alpha. ( i ) = tan - 1 P y ( i ) . ##EQU00002##
[0012] Optionally, the magnification ratio .beta..sub.(i) of the
two adjacent microstructures satisfies the formula:
.beta. ( i ) = .DELTA. l z ( i + 1 ) .DELTA. l .PHI. ( i )
##EQU00003##
wherein .DELTA.l.sub.z(i+1) is the length of the parabola between
the centerlines of the two adjacent microstructures along the z
direction in the coordinate system of the parabola; and
.DELTA.l.sub..phi.(i) is the diameter of the bottom surface of each
microstructure.
[0013] Optionally, the curved surface is recessed in the LGP or
projected out of the LGP.
[0014] Optionally, the spherical curved surfaces of all the mesh
points on the LGP have same curvature radius.
[0015] The embodiment of the present disclosure further provides a
display device, which comprises any foregoing LGP.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Simple description will be given below to the accompanying
drawings of the embodiments to provide a more clear understanding
of the technical proposals of the embodiments of the present
disclosure. Obviously, the drawings described below only involve
some embodiments of the present disclosure but are not intended to
limit the present disclosure.
[0017] FIG. 1a is a schematic diagram illustrating a light
propagation path in an LGP;
[0018] FIG. 1b is a schematic diagram illustrating the light
propagation path in another LGP;
[0019] FIG. 1c is a bottom view of the LGP as shown in FIG. 1b;
[0020] FIG. 2a is a schematic structural view of an LGP provided by
an embodiment of the present disclosure;
[0021] FIG. 2b is a schematic structural view of a mesh point
provided by the embodiment of the present disclosure;
[0022] FIG. 2c is a schematic structural partial view of the LGP
provided by an embodiment of the present disclosure;
[0023] FIG. 2d is a schematic structural view of a microstructure
provided by an embodiment of the present disclosure;
[0024] FIG. 2e is a schematic structural view of another LGP
provided by an embodiment of the present disclosure;
[0025] FIG. 3 is a schematic structural view of another mesh point
provided by an embodiment of the present disclosure;
[0026] FIG. 4 is a mesh point distribution design diagram provided
by an embodiment of the present disclosure; and
[0027] FIG. 5 is another mesh point distribution design diagram
provided by an embodiment of the present disclosure.
[0028] Reference numerals of the accompanying drawings:
10-LGP; A-Reflecting surface of LGP; B-Light-emitting surface of
LGP; 101-Mesh Points; 100-Bottom surface of Mesh Point;
201-Microstructure; 202-Top Surface of Microstructure; 203-Bottom
Surface of Microstructure; L1, L2-Circumference of Cross-section of
Spherical Curved Surface; o'-Vertex of Spherical Curved Surface;
o-Low End of Spherical Curved Surface (Original Point of Coordinate
System of Parabola); P-Parabola; 30-Side-lit Light Source;
301-Portion of light-emitting surface of LGP Close to Side-lit
Light Source; 302-Portion of Reflecting Surface of LGP away from
Side-lit Light Source.
DETAILED DESCRIPTION
[0029] For more clear understanding of the objectives, technical
proposals and advantages of the embodiments of the present
disclosure, clear and complete description will be given below to
the technical proposals of the embodiments of the present
disclosure with reference to the accompanying drawings of the
embodiments of the present disclosure. Obviously, the preferred
embodiments are only partial embodiments of the present disclosure
but not all the embodiments. All the other embodiments obtained by
those skilled in the art without creative efforts on the basis of
the embodiments of the present disclosure illustrated shall fall
within the scope of protection of the present disclosure.
[0030] FIG. 1a is a schematic diagram illustrating the light
propagation path in an LGP; FIG. 1b is a schematic diagram
illustrating the light propagation path in another LGP; and FIG. 1c
is a bottom view of the LGP as shown in FIG. 1b. As illustrated in
FIG. 1a, as an included angle .alpha. between incident light X
entering an LGP 10 and a reflecting surface A of the LGP 10 is
large, after the incident light X is reflected on the reflecting
surface A an incidence angle .beta. of the incident light X on a
light-emitting surface B of the LGP 10 is large. As the incidence
angle .beta. of the light on the light-emitting surface B is less
than a refraction angle 0, the refraction angle .theta. is larger
when the incidence angle .beta. is larger. When the incidence angle
.beta. is greater than a critical value (as shown by solid arrows
in FIG. 1), the refraction angle 0 is 90.degree.. In this way, the
light incident to the light-emitting surface B cannot be emitted
from the LGP and is reflected to the LGP 10, namely the light is
subjected to total reflection on the light-emitting surface B of
the LGP 10.
[0031] In order to reduce the total reflection phenomenon on the
light-emitting surface B of the LGP 10, as illustrated in FIG. 1b,
mesh points 101 are formed on the reflecting surface A of the LGP;
and as illustrated in FIG. 1c, the mesh points 101 are, for
instance, regularly formed on a bottom surface of the LGP and are
in a mesh pattern as a whole. The light in the LGP 10 is irradiated
to the mesh points 101 and reflected to the light-emitting surface
B of the LGP 10. As the surface of the mesh point 101 for
reflection is a curved surface, the curved surface will reduce the
incidence angle .beta. of the reflected light on the light-emitting
surface B of the LGP 10, so that the light can be emitted from the
light-emitting surface B of the LGP 10, and hence the total
reflection phenomenon on the light-emitting surface B of the LGP 10
can be reduced.
[0032] However, for the purpose of convenience of processing, the
curved surfaces of all the mesh points 101 on the reflecting
surface A of the LGP 10 have same curvature ratio, but the included
angle a between the light irradiated to different mesh points 101
and the reflecting surface A of the LGP 10 is different. As
illustrated in FIG. 1b, the included angle .alpha.' of the light
represented by the dashed line is greater than the included angle a
of the light represented by the solid line. Therefore, after the
light represented by the dashed line is reflected by the mesh point
101, the incidence angle .beta.' of the light on the light-emitting
surface B of the LGP 10 is large, so that the light cannot be
emitted from the light-emitting surface B of the LGP, and hence the
total reflection phenomenon still occurs. After the light
represented by the solid line is reflected by the mesh point 101,
the incidence angle .beta. of the light on the light-emitting
surface B of the LGP 10 is small, so that the light can be emitted
from the light-emitting surface B of the LGP. In this way, a
portion of the light-emitting surface B of the LGP 10, from which
the light can be emitted, has high brightness, so that the portion
from which the light cannot be emitted has low brightness, and
hence the luminous uniformity of the LGP can be reduced. Moreover,
obvious intense and weak light areas will be presented on the
display panel. As intense light and weak light are staggered, the
luminous phenomenon of flickering like fireflies will occur. The
firefly phenomenon will disadvantageously affect the display effect
of the display and reduce the performances of the display.
[0033] An embodiment of the present disclosure provides an LGP 10,
which, as illustrated in FIG. 2a, may comprise at least one mesh
point 101 provided with microstructures 201. Mesh points 101 may be
regularly distributed on a surface of the LGP, for instance,
uniformly distributed as shown in FIG. 1c, and may also be, for
instance, sparsely distributed in the middle portion and densely
distributed on the circumference portion. At least one mesh point
is provided with the microstructures, namely not all the mesh
points are required to have the microstructures. As illustrated in
FIG. 2b, all the microstructures 201 on each mesh point 101 are
arranged on the same curved surface 120 of the mesh point 101. The
curved surface 120 is a projected outer surface of the mesh point
101.
[0034] As seen from FIG. 2c, namely the partial view of C in FIG.
2a, the incidence angle .beta. of the light irradiated to the
microstructure 201 (represented by the solid line) on the
light-emitting surface B of the LGP 10 after reflection is less
than the incidence angle .beta.' of the light not irradiated to the
microstructure 201 (represented by the dashed line) on the
light-emitting surface B of the LGP 10 after reflection. Therefore,
the light reflected to the light-emitting surface B of the LGP 10
can be refracted via the microstructure 201 and hence emitted from
the LGP 10. Moreover, as the number of the microstructures 201 is
larger, the number of the light capable of changing the light
propagation path in the LGP 10 is larger, so that the luminous
efficiency of the LGP 10 can be more effectively improved.
[0035] An embodiment of the present disclosure provides an LGP,
which may comprise at least one mesh point provided with
microstructures. All the microstructures on each mesh point are
arranged on the same curved surface. In this way, when light is
irradiated to the mesh point, the curvature of a light contact
position on the curved surface of the mesh point may be increased
via the microstructures, so that the incidence angle of the light,
reflected on the microstructures, on a light-emitting surface of
the LGP can be reduced, and hence the light can be emitted from the
LGP. Therefore, the total reflection phenomenon of a portion of
light required to be refracted that occurs due to the small
included angle between the reflected light and the LGP can be
avoided; the luminous efficiency of the light on the light-emitting
surface of the LGP can be improved; and hence the luminous
uniformity and the display effect can be improved.
[0036] It should be noted that: firstly, the curved surface 120 may
have a regular curvature distribution shape or an irregular
curvature distribution shape. No limitation will be placed in this
regard in the present disclosure.
[0037] In the process of manufacturing the LGP 10, a drill bit is
usually adopted to hit an LGP motherboard to form a mesh point
model, and subsequently a material layer for forming the LGP 10 is
formed on the motherboard. As a result, partial material layer will
flow into or bypass the mesh point model so as to form the curved
surface 120 projected out of the LGP 10 or recessed in the LGP
10.
[0038] In the actual manufacturing process, for the convenience of
processing, for instance, the drill bit is generally spherical, so
the curved surface obtained by the above manufacturing method is a
spherical curved surface with regular curvature distribution.
[0039] For instance, the spherical curved surfaces of all the mesh
points 101 on the LGP 10 have a same curvature radius. In this way,
the mesh points on the LGP 10 can be formed by a uniform
manufacturing process, and hence the manufacturing process can be
simplified and the manufacturing difficulty can be reduced.
[0040] Secondly, the shapes of the top surfaces 202 of the
microstructures 201 and the bottom surfaces 203 of the
microstructures 201 are not limited.
[0041] In order to simplify the manufacturing process, in the
process of manufacturing the mesh points provided with the
microstructures 201, the drill bit may be slightly ground, so that
the surfaces of the mesh points can be rough, and hence the
microstructures 201 can be formed. Therefore, in the grinding
process, a surface of a portion of the drill bit for forming the
microstructure 201 is ground into a cambered surface. Thus, as
illustrated in FIG. 2d, the top surface 202 of the formed
microstructure 201 may be a cambered surface.
[0042] The bottom surface 203 of the microstructure 201 may be
manufactured into a regular shape according to the processing
difficulty and the actual need, e.g., quadrangle as shown in FIG.
2d, or other polygons such as pentagon and hexagon. Or the bottom
surface 203 of the microstructure 201 may also be circular. Of
course, the bottom surface 203 may also be manufactured into other
irregular shapes.
[0043] Thirdly, the distribution rule of the mesh points 101 on the
LGP 10 is not limited in the present disclosure and may be set
according to actual needs.
[0044] For instance, as illustrated in FIG. 2e, as for a side-lit
backlight, as a side-lit light source 30 is disposed on one side of
the LGP 10, incident light on a portion 301 of the light-emitting
surface B of the LGP 10 close to the side-lit light source 30 must
be led into the other side of the LGP 10 through total reflection
of the light on the light-emitting surface B. Therefore, a few mesh
points 101 may be formed on a portion 301 of the reflecting surface
A of the LGP 10 close to the side-lit light source 30, so that the
partial total reflection phenomenon of the light-emitting surface B
can be retained, and hence the totally reflected light can be
further transmitted towards the other side of the LGP 10. A portion
302 of the reflecting surface A of the LGP 10 away from the
side-lit light source 30 may be provided with a plurality of mesh
points 101, so that the total reflection phenomenon of the portion
on the light-emitting surface B of the LGP 10 away from the
side-lit light source can be reduced, and hence the light output
rate of the light-emitting surface B of the LGP 10 can be
improved.
[0045] Moreover, for instance, as for a direct-lit backlight, as
the light source is disposed on one side of the reflecting surface
A of the LGP, light emitted from the light source can
simultaneously enter the LGP 10. Thus, the mesh points 101 may be
uniformly distributed on the reflecting surface A of the LGP 10, as
long as the mesh points 101 provided with the microstructures are
disposed at positions at which total reflection is required to be
reduced so that the total reflection phenomenon of the part of
light required to be refracted that occurs due to the small
included angle between the reflected light and the LGP can be
avoided.
[0046] Illustration will be given below to the design proposal of
the microstructure 201 with reference to the preferred
embodiments.
Embodiment 1
[0047] If the curved surface 120 is a spherical curved surface, in
order to simplify the manufacturing process and improve the
luminous uniformity, the microstructures 201 on the curved surface
arranged on the same circumference (for instance, a circle of
microstructures 201 arranged along a circumference L1, or a circle
of microstructures 201 arranged along a circumference L2) may, as
illustrated in FIG. 2b, have a same shape and size. A plane
provided with the circumference (e.g., the circumference L1 or L2)
is parallel to the light-emitting surface B of the LGP 10.
[0048] For instance, the shapes and the sizes of the
microstructures 201 respectively disposed on two adjacent
circumferences L1 and L2 may be same as each other.
[0049] However, as illustrated in FIG. 2b, as for the spherical
curved surface 120, the diameter of a cross-section (the
cross-section intercepted by a plane parallel to a bottom surface
100 of the mesh point 101) of the spherical surface is gradually
expanded from a vertex o' of the spherical curved surface 120 to a
center o of a circumference at a low end of the spherical curved
surface 120, which indicates that: the perimeter of the
cross-section (e.g., the cross-section provided with the
circumference L2) close to the low end o of the spherical curved
surface 120 is large, and the space for arranging the
microstructures 201 is also large; and the perimeter of the
cross-section (e.g., the cross-section provided with the
circumference L1) close to the vertex o' of the spherical curved
surface 120 is small, and the space for arranging the
microstructures 201 is also small. Therefore, areas, at which the
microstructures 201 can be arranged, of the spherical curved
surface 120 become more along the negative direction of the z axis.
Therefore, the present disclosure provides another solution for
arranging the microstructures 201. Detailed description will be
given in the next embodiment.
Embodiment 2
[0050] As illustrated in FIG. 3, the curved surface 120 may be
bisected by N parabolas P; a starting point of the parabola P is
the vertex o' of the curved surface 120, and an end point is
disposed on the bottom surface 100 of the mesh point 101, wherein
N.gtoreq.1.
[0051] As the perimeter of the Cross-section of the spherical
curved surface 120 is gradually increased along the negative
direction of the z axis and larger microstructures can be arranged,
the microstructures 201 are sequentially arranged from the starting
point o' to the end point of the parabola and have same shape, and
the sizes thereof are gradually increased.
[0052] As the mesh point 101 has a very small size, if the
microstructures 201 are all manufactured into an equal and small
size, the requirements on the manufacturing difficulty and the
manufacturing accuracy can be greatly increased. In the above
solution, the microstructures 201 with a small size are only
required to be manufactured on partial spherical curved surface 120
close to the vertex o'. When the diameter of the cross-section of
the spherical curved surface 120 is gradually increased, the sizes
of the microstructures 201 are also correspondingly increased.
Therefore, the manufacturing accuracy and the manufacturing
difficulty can be reduced and the production efficiency can be
improved.
[0053] Detailed description will be given in the following
embodiment to the specific arrangement process of the
microstructures 201 on the basis of the size, arrangement and
distribution of the microstructures 201 provided by the embodiment
2.
Embodiment 3
[0054] As the equation of the parabola P may be y.sup.2=2Pz, in
which P=2f, and f is the focal length of the parabola. As
illustrated in FIG. 3, when the parabola P rotates around the z
axis for a circle, the spherical curved surface 120 may be
obtained.
[0055] As seen from the equation of the parabola P, the radius of
the cross-section of the spherical curved surface 120 at the origin
of coordinate o is y= {square root over (2Pz)}.
[0056] Supposing that the radius of a cross-section (e.g., a
cross-section in which z.ltoreq.f) is y.sub.(i), the perimeter of
the cross-section (e.g., the circumference L1) is as follows:
C.sub.(i)=2.pi.y.sub.(i)=2.pi. {square root over (2Pz.sub.(i))},
i=0,.+-.1,.+-.2,.+-.3 . . .
[0057] If n microstructures 201 may be placed on the circumference
L1, the size of each microstructure 201 (when the bottom surface of
the microstructure 201 is circular, the size may be referred to
diameter) is as follows:
.DELTA. l .PHI. ( i ) = C ( i ) n = 2 .pi. y ( i ) n = y ( i )
.DELTA..PHI. , i = 0 , .+-. 1 , .+-. 2 , .+-. 3 ( 1 )
##EQU00004##
[0058] Therefore, the size (diameter) of each microstructure 201
arranged on the circumference L1 or L2 may be obtained according to
the perimeter of the cross-section (e.g., the circumference L1 or
L2) on the spherical curved surface 120.
[0059] In summary, by adoption of the arrangement method, the
bottom surface 203 of the formed microstructure 201 is circular. It
should be noted that the shape of the bottom surface 203 of the
microstructure 201 refers to the shape of the planar graph of the
orthographic projection of the bottom surface 203 of the
microstructure 201 towards the curved surface 120.
[0060] The shape of the bottom surface 203 of the microstructure
201 may be set to be quadrangle or pentagon. Taking quadrangle as
an example, in the arrangement process, as illustrated in FIG. 4,
two adjacent microstructures 201, of which the bottom surfaces 203
are circular, arranged on the circumference L1 or L2 may be
considered to be overlapped, and overlapped portions are finally
required microstructure portions. At this point, the orthographic
projection of the bottom surface 203 of the microstructure 201
towards the spherical curved surface 120 is a quadrangle.
[0061] In order to adopt the above overlapping method to allow the
bottom surface 203 of the microstructure 201 to be a quadrangle or
a pentagon, a central position of the microstructure 201 may be
intercepted on the spherical curved surface 120 with the curvature
radius of R by taking .DELTA.l.sub..phi.(i) as the radius. When the
curvature radius R of the spherical curved surface 120 is larger,
the included angle .DELTA..phi. between centerlines of two adjacent
microstructures 201 is smaller, vice versa.
[0062] In addition, as illustrated in FIG. 5, in the arrangement
process, after the parabola P is increased by .DELTA.z.sub.(i+1)
along the negative direction of the z axis, the length of a
generatrix of the parabola P must be increased by
.DELTA.l.sub.z(i+1). Therefore, the coordinate y.sub.(i) of the
microstructure 201 in the y direction is increased by
.DELTA.y.sub.(i+1). That is to say,
y.sub.(i-1)=y.sub.(i)+.DELTA.y.sub.(i+1) can be obtained when
.DELTA.l.sub.z(i+1)=.DELTA.l.sub..phi.(i), namely the two adjacent
microstructures 201, of which the bottom surfaces 203 are circular,
arranged on the circumference L1 or L2 are overlapped with each
other.
[0063] The following formulas can be obtained from FIG. 5:
.DELTA.l.sub.z(i+1).sup.2=.DELTA.z.sub.(i+1).sup.2+.DELTA.y.sub.(i+1).su-
p.2 (2)
.DELTA.z.sub.(i+1).sup.2+.DELTA.y.sub.(i+1).sup.2=[(y.sub.i+.DELTA.y.sub-
.(i+1)).DELTA..phi.].sup.2 (3)
[0064] By taking the derivation of the equation y.sup.2=2 Pz of the
parabola P, 2 ydy=2 Pdz is obtained; and the following formula is
obtained by taking a finite quantity:
.DELTA. y ( i + 1 ) = P y ( i ) .DELTA. z ( i + 1 ) . ( 4 )
##EQU00005##
[0065] The formula (4) is brought into the formula (3) and the
following is obtained:
.DELTA. z ( i + 1 ) 2 + ( P y ( i ) .DELTA. z ( i + 1 ) ) 2 = [ ( y
( i ) + P y ( i ) .DELTA. z ( i + 1 ) ) .DELTA..PHI. ] 2 , ( 5 )
##EQU00006##
and then the formula which the position of the microstructures 201
arranged on the parabola P should satisfy may be obtained:
[ 1 + P y ( i ) ( 1 - .DELTA..PHI. 2 ) ] .DELTA. z ( i + 1 ) 2 - 2
P .DELTA. z ( i + 1 ) - y ( i ) 2 .DELTA..PHI. 2 = 0 ( 6 )
##EQU00007##
wherein P is twice larger than the focal length f of the parabola
P; y.sub.(i) is the coordinate of the microstructure 201 in the y
direction in the coordinate system of the parabola P (as shown in
FIG. 5); .DELTA.z.sub.(i+1) is the distance between centerlines of
two adjacent microstructures 201 along the z direction in the
coordinate system of the parabola P; and .DELTA..phi. is an
included angle between the centerlines of the two adjacent
microstructures 201 on the parabola P.
[0066] Moreover, after the focal length f of the parabola P and the
coordinate z.sub.(i) of the circumference L1 in the z axis are
determined, the radius y.sub.(i) of the circumference L1 can be
obtained. In addition, after the number n of the microstructures
201 required to be arranged on the circumference L1 is determined,
the included angle .DELTA..phi. between the centerlines of the two
adjacent microstructures 201 can be obtained. As
z.sub.(i+1)=z.sub.(i).DELTA.z.sub.(i+1), the following formula can
be obtained by substituting known quantities into the formula
(6):
.DELTA.l.sub.(1)= {square root over
(.DELTA.z.sub.(1).sup.2+.DELTA.y.sub.(1).sup.2)}.
[0067] Moreover, 2 ydy=2 Pdz can be obtained by taking the
derivation of the equation y.sup.2=2 Pz of the parabola P through
the equation (6), and the following formula which is satisfied by
the inclination angle .alpha..sub.(i) of each microstructure 201 on
the parabola P can be obtained:
.alpha. ( i ) = tan - 1 P y ( i ) . ##EQU00008##
[0068] Furthermore, the magnification ratio .beta..sub.(i) of the
two adjacent microstructures 201 satisfies the formula:
.beta. ( i ) = .DELTA. l z ( i + 1 ) .DELTA. l .PHI. ( i )
##EQU00009##
[0069] wherein .DELTA.l.sub.z(i+1) is the length of the parabola
between the centerlines of the two adjacent microstructures along
the z direction in the coordinate system of the parabola; and
.DELTA.l.sub..phi.(i) is the diameter of the bottom surface of each
microstructure 201.
[0070] When the coordinate, the inclination angle and the
magnification of the microstructure 201 have all been known, the
mesh points 101 provided with the microstructures 201 as shown in
FIG. 6 are arranged by the above method. FIG. 6 is a top view of
the spherical curved surface 120. And not all the microstructures
201 have been drawn in the drawing.
[0071] For instance, when the number of the microstructures 201 on
the curved surface 120 of the mesh point 101 is 100, five layers
may be arranged and each layer includes 20 microstructures 201. The
focal length of the parabola P provided with the microstructures is
set to be 5 mm. The specific data of 10 microstructures 201 in the
100 microstructures 201 are as shown in the table 1.
TABLE-US-00001 TABLE 1 Radius of Microstructure Magnification
Inclination Angle .alpha. of Microstructure (mm) Ratio .beta.
Microstructure No. 0.8886 1 35.2644 1 0.9214 1.03696 34.2903 2
0.9546 1.03605 33.3521 3 0.9882 1.03516 32.4491 4 1.0221 1.03430
31.5806 5 1.0563 1.03346 30.7455 6 1.0908 1.03265 29.9429 7 1.1256
1.03187 29.1716 8 1.1606 1.03111 28.4306 9 1.1958 1.03037 27.7187
10
[0072] The following data can be obtained by the illumination
simulation of the mesh points not provided with the microstructures
201 and the mesh points provided with the microstructures 201 via
software.
[0073] The data of the LGP 100 comprising the mesh points 101 not
provided with the microstructures 201 are as shown in the table
2:
TABLE-US-00002 TABLE 2 Minimum (M) 242.70 Lux Contrast Ratio (C)
0.15720 Maximum (X) 333.24 Lux Standard Deviation (D) 16.812
Average (A) 291.83 Lux Mean Variation (V) 0.057611
[0074] The data of the LGP 10 comprising the mesh points 101
provided with the microstructures 201 are as shown in the table
3:
TABLE-US-00003 TABLE 3 Minimum (M) 263.80 Lux Contrast Ratio (C)
0.19239 Maximum (X) 389.48 Lux Standard Deviation (D) 20.976
Average (A) 326.93 Lux Mean Variation (V) 0.064161
[0075] In summary, as shown in the table 2, the illumination
intensity of the LGP 10 comprising the mesh points 101 not provided
with the microstructures 201 is mostly distributed at 300 Lux; and
the illumination intensity of the LGP 10, comprising the mesh
points 101 provided with the microstructures 201, provided by the
embodiment of the present disclosure is mostly distributed at 300
Lux-400 Lux. Therefore, as can be obviously seen, the luminous
efficiency of the LGP 10 provided by the embodiments of the present
disclosure is improved, and hence the display effect of the display
device can be improved.
[0076] An embodiment of the present disclosure provides a display
device, which comprises any foregoing LGP 10 and has the structure
and the advantages the same with the LGP 10 provided by the
foregoing embodiment. As detailed description has been given to the
structure and the advantages of the LGP 10 in the foregoing
embodiment, no further description will be given here.
[0077] In an embodiment of the present disclosure, the display
device may specifically comprise an LCD device. For instance, the
display device may be any product or component with display
function such as an LCD, an LCD TV, a digital picture frame, a
mobile phone and a tablet PC.
[0078] The foregoing is only the preferred embodiments of the
present disclosure and not intended to limit the scope of
protection of the present disclosure. The scope of protection of
the present disclosure should be defined by the appended claims
[0079] The application claims priority to the Chinese patent
application No. 201510005708.0, filed Jan. 6, 2015, the disclosure
of which is incorporated herein by reference as part of the
application.
* * * * *